The invention is related to a device for securing the upper thread loop after threading the upper thread into the eye of a sewing machine needle.
For decades, manually operated or fully automatically operating threading devices have been known for threading the upper thread of a sewing machine through the eye of the sewing needle. For threading, the upper thread is caught via a threading or catching hook, which is guided through the eye of the needle, and a loop is formed behind the eye of the needle. This thread loop can later be grabbed manually and the loose end can be pulled through the eye. This manipulation latently bears the risk that, when grabbing the loop extending through the eye of the needle, it can be pulled back out of the eye of the needle due to the fact that it is relatively short or due to a movement of the take-up lever, and thus the threading process has to be repeated.
In order to prevent this, a threading device is known from U.S. Pat. No. 5,615,629, in which the thread located in the threading or catching hook is held by a wire holder in a clamped manner. Here, the upper thread is pressed by the wire holder into the chamfer of the hook. In order to allow the thread loop to be released for the sewing process, the wire holder with a link is guided out of the hook when the threading device is raised, subsequently allowing the thread loop to drop off the catching hook.